Hmm, well, let's consider what's afoot as far as new FR source material between now and when we start building:
10/2006 - Road of the Patriarch (Sellswords, may interest Cold Lands, do not believe it goes further than 1374 DR)
09/2006 - The Twilight Tomb (FR adventure, based in Aglarond, no date provided as of yet)
09/2006 - Lies of Light (Book II in the Watercourse trilogy where a Watercourse/canal is being created to link the Inner Sea to the western seas of Faerûn's coast, may effect portals in the regions effected as far as where one can sail to and from to reach certain points)
08/2006 - Swords of Eveningstar (Set in the past, no effect on timeline)
08/2006 - Dragons of Faerûn (Details the events of Rogue Dragons and all things draconic)
While there are a few other products, none is of note (several older books reprinted, et cetera). So, I'd recommend starting simply at the end of the year 1374 DR, the end of the Last Mythal, where the elves have returned, as there will be no other large canon changes between now and when we start building.
What this means:
City of Shade has returned,
Phaerimm attack Evereska and Llorkh (other nearby places),
Shade nearly crashes into the desert,
Tilverton is destroyed,
Elminster has been through Hell and back,
the Silence of Lolth has came and gone,
Ched Nasad is destroyed and rebuilt by the half-shadow dragons who enginereed its downfall,
Menzo has repelled a fierce attack by the combined armies of the Scoured Legion and Gracklstugh,
the Monastery of the Yellow Rose sees much structural damage when a flight of dragons attacks it,
Sammaster is slain (again, he never quite stays dead) and the Cult of the Dragon severely decimated (again, it never quite stays dead),
much of Llorkh is destroyed by rampaging Thunderbeasts from the High Forest (the temple of Cyric there is reduced to rubble and the high priest slain just prior to this attack when he attempts to despoil the Unicorn Run with twisted magickar),
One of the twin towers of the eternal eclipse are stolen away by a power made ancient spellcaster to fuel a spell which causes Selune's largest tear to cause a long eclipse before plummeting toward Toril causing quite the scare, but burning up in the atmosphere and causing no notable damage in the end,
The Sothillisian Empire occupying the city of Murann in southern Amn forms a temporary truce and uneasy alliance of sorts with the nation of Amn when an army of angry stingers from Maztica attacks from the Underdark below, demanding the return of treasures plundered from far off Maztica, beginning the Stinger War (see Power of Faerûn) for details,
the Daemonfey free their legions from within the Nameless Dungeon, using the Gatekeeper crystal, and obliterating a large section of that ruin (High Forest)
an army of elves pushes the Daemonfey away from elven ruins within the vicinity of the High Forest and through a network of portals to Cormanthor,
the elven forces follow the Daemonfey to Cormanthor and find them facing off against more enemies than they expected Zhentil Keep, Hillsfar, and Sembia join the Daemonfey cause briefly causing much trouble for several southern dales (Mistledale and Deepingdale see the worst of it)
in the end the Daemonfey are destroyed utterly, the fiends are cast out of Myth Drannor, Sembia is now in much better standing with the elves and people of the Dalelands since they eventually joined the elven cause agains the Daemonfey, the elves retake Myth Drannor, Zhentil Keep marches on Hillsfar and demands annual tribute (no battle occurs, the lord of Hillsfar has gone into hiding after an attack on him within his city by the Daemonfey angry with him for not aiding the Zhentarim in a planned attack on Shadowdale and Mistledale).
That brings us up to date, though, I may have missed some tidbits.
